Computing Covers of 2D-Strings

Authors Panagiotis Charalampopoulos , Jakub Radoszewski , Wojciech Rytter , Tomasz Waleń , Wiktor Zuba



PDF
Thumbnail PDF

File

LIPIcs.CPM.2021.12.pdf
  • Filesize: 0.86 MB
  • 20 pages

Document Identifiers

Author Details

Panagiotis Charalampopoulos
  • The Interdisciplinary Center Herzliya, Israel
Jakub Radoszewski
  • University of Warsaw, Poland
Wojciech Rytter
  • University of Warsaw, Poland
Tomasz Waleń
  • University of Warsaw, Poland
Wiktor Zuba
  • University of Warsaw, Poland

Cite AsGet BibTex

Panagiotis Charalampopoulos, Jakub Radoszewski, Wojciech Rytter, Tomasz Waleń, and Wiktor Zuba. Computing Covers of 2D-Strings. In 32nd Annual Symposium on Combinatorial Pattern Matching (CPM 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 191, pp. 12:1-12:20, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)
https://doi.org/10.4230/LIPIcs.CPM.2021.12

Abstract

We consider two notions of covers of a two-dimensional string T. A (rectangular) subarray P of T is a 2D-cover of T if each position of T is in an occurrence of P in T. A one-dimensional string S is a 1D-cover of T if its vertical and horizontal occurrences in T cover all positions of T. We show how to compute the smallest-area 2D-cover of an m × n array T in the optimal 𝒪(N) time, where N = mn, all aperiodic 2D-covers of T in 𝒪(N log N) time, and all 2D-covers of T in N^{4/3}⋅ log^{𝒪(1)}N time. Further, we show how to compute all 1D-covers in the optimal 𝒪(N) time. Along the way, we show that the Klee’s measure of a set of rectangles, each of width and height at least √n, on an n × n grid can be maintained in √n⋅ log^{𝒪(1)}n time per insertion or deletion of a rectangle, a result which could be of independent interest.

Subject Classification

ACM Subject Classification
  • Theory of computation → Pattern matching
Keywords
  • 2D-string
  • cover
  • dynamic Klee’s measure problem

Metrics

  • Access Statistics
  • Total Accesses (updated on a weekly basis)
    0
    PDF Downloads

References

  1. Amihood Amir, Ayelet Butman, Eitan Kondratovsky, Avivit Levy, and Dina Sokol. Multidimensional period recovery. In String Processing and Information Retrieval - 27th International Symposium, SPIRE 2020, volume 12303 of Lecture Notes in Computer Science, pages 115-130. Springer, 2020. URL: https://doi.org/10.1007/978-3-030-59212-7_9.
  2. Alberto Apostolico, Martin Farach, and Costas S. Iliopoulos. Optimal superprimitivity testing for strings. Information Processing Letters, 39(1):17-20, 1991. URL: https://doi.org/10.1016/0020-0190(91)90056-N.
  3. Theodore P. Baker. A technique for extending rapid exact-match string matching to arrays of more than one dimension. SIAM Journal on Computing, 7(4):533-541, 1978. URL: https://doi.org/10.1137/0207043.
  4. Jon Louis Bentley. Algorithms for Klee’s rectangle problems. Unpublished notes, Computer Science Department, Carnegie Mellon University, 1977. Google Scholar
  5. Jon Louis Bentley. Multidimensional divide-and-conquer. Communications of the ACM, 23(4):214-229, 1980. URL: https://doi.org/10.1145/358841.358850.
  6. Richard S. Bird. Two dimensional pattern matching. Information Processing Letters, 6(5):168-170, 1977. URL: https://doi.org/10.1016/0020-0190(77)90017-5.
  7. Dany Breslauer. An on-line string superprimitivity test. Information Processing Letters, 44(6):345-347, 1992. URL: https://doi.org/10.1016/0020-0190(92)90111-8.
  8. Timothy M. Chan. Klee’s measure problem made easy. In 54th Annual IEEE Symposium on Foundations of Computer Science, FOCS 2013, pages 410-419. IEEE Computer Society, 2013. URL: https://doi.org/10.1109/FOCS.2013.51.
  9. Panagiotis Charalampopoulos, Jakub Radoszewski, Wojciech Rytter, Tomasz Waleń, and Wiktor Zuba. The number of repetitions in 2D-strings. In 28th Annual European Symposium on Algorithms, ESA 2020, volume 173 of LIPIcs, pages 32:1-32:18. Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2020. URL: https://doi.org/10.4230/LIPIcs.ESA.2020.32.
  10. Michalis Christou, Maxime Crochemore, and Costas S. Iliopoulos. Quasiperiodicities in Fibonacci strings. Ars Combinatoria, 129:211-225, 2016. Google Scholar
  11. Maxime Crochemore, Costas S. Iliopoulos, and Maureen Korda. Two-dimensional prefix string matching and covering on square matrices. Algorithmica, 20(4):353-373, 1998. URL: https://doi.org/10.1007/PL00009200.
  12. Maxime Crochemore and Wojciech Rytter. Jewels of Stringology. World Scientific, 2002. URL: https://doi.org/10.1142/4838.
  13. Nathan J. Fine and Herbert S. Wilf. Uniqueness theorems for periodic functions. Proceedings of the American Mathematical Society, 16(1):109-114, 1965. URL: https://doi.org/10.2307/2034009.
  14. Donald E. Knuth, James H. Morris Jr., and Vaughan R. Pratt. Fast pattern matching in strings. SIAM Journal on Computing, 6(2):323-350, 1977. URL: https://doi.org/10.1137/0206024.
  15. Tomasz Kociumaka, Jakub Radoszewski, Wojciech Rytter, and Tomasz Waleń. Internal pattern matching queries in a text and applications. In Proceedings of the Twenty-Sixth Annual ACM-SIAM Symposium on Discrete Algorithms, SODA 2015, pages 532-551. SIAM, 2015. URL: https://doi.org/10.1137/1.9781611973730.36.
  16. Dennis W. G. Moore and William F. Smyth. An optimal algorithm to compute all the covers of a string. Information Processing Letters, 50(5):239-246, 1994. URL: https://doi.org/10.1016/0020-0190(94)00045-X.
  17. Dennis W. G. Moore and William F. Smyth. A correction to "An optimal algorithm to compute all the covers of a string". Information Processing Letters, 54(2):101-103, 1995. URL: https://doi.org/10.1016/0020-0190(94)00235-Q.
  18. Mark H. Overmars and Chee-Keng Yap. New upper bounds in Klee’s measure problem. SIAM Journal on Computing, 20(6):1034-1045, 1991. URL: https://doi.org/10.1137/0220065.
  19. Alexandru Popa and Andrei Tanasescu. An output-sensitive algorithm for the minimization of 2-dimensional string covers. In Theory and Applications of Models of Computation - 15th Annual Conference, TAMC 2019, volume 11436 of Lecture Notes in Computer Science, pages 536-549. Springer, 2019. URL: https://doi.org/10.1007/978-3-030-14812-6_33.
Questions / Remarks / Feedback
X

Feedback for Dagstuhl Publishing


Thanks for your feedback!

Feedback submitted

Could not send message

Please try again later or send an E-mail